The present invention relates to aerial bombs, that is, bombs dropped from aircraft, and more particularly, to aerial bombs for penetrating hard targets.
A bomb typically includes a hard casing having an interior hollow space for containing an explosive material. The physical characteristics of the bomb, including the weight, center of gravity, moments or inertia, and the aerodynamic shape, all affect the free-fall response of the bomb, whether or not a guidance package is included with the bomb.
Bombs delivered from aircraft, including free-fall guided or unguided bombs, glide bombs, and boosted bombs, must pass rigorous field testing which includes the safe release from a deploying aircraft and accuracy of delivery to the target. These tests must be conducted for each type of aircraft that will carry the bomb. The development of new weapons, therefore, is subject to significant delay and expense before the weapon is qualified for use.
The ability of a bomb, or other projectile, to penetrate a target is proportional to the mass and the velocity of impact of the projectile and inversely proportional to the cross-sectional area of the bomb. That is, the greater the kinetic energy and the smaller the cross-sectional area, the greater the penetration that can be expected. To adapt an existing bomb for greater penetration by reducing the external diameter of the bomb can also result, however, in changes in the mass properties such as weight, center of gravity, moment of inertia, and in the aerodynamic properties, all of which can affect the flight characteristics of the bomb. These changes also require that the adapted bomb be qualified for use.
The present invention provides an aerial bomb that overcomes the difficulty in qualification by emulating the pertinent aerodynamic characteristics and mass properties of a qualified bomb, while providing a function not provided by that bomb.
More particularly, the present invention provides a bomb having an improved penetrating warhead, that is, a warhead that more deeply penetrates a protected target, however, the bomb is substantially identical in aerodynamic and mass properties to a qualified bomb. As a result, the bomb of the present invention may be readily qualified by similarity of function to the existing bomb for use on an aircraft In addition, if desired, the bomb of the invention can use existing guidance packages available for the qualified bomb.
To avoid lengthy and expensive delays required to qualify a new bomb, the invention provides a bomb that emulates the free-fall properties of an existing bomb pertinent to qualification, while at the same time, providing a warhead with the desired improved penetrating capability.
According to the invention, the warhead is a penetrating body shaped for improved target penetration through a smaller cross-sectional area compared to an existing qualified bomb. An aerodynamic shroud mounted around the warhead emulates the shape of the qualified bomb, and the weight, center of gravity and moments of inertia of the bomb (the penetrating body and shroud) closely approximate those properties of the existing bomb.